Abstract
133Xenon clearance technique as a measure of the blood flow per unit weight of muscle tissue has been compared to venous occlusion plethysmography in the calf of normal subjects. The comparison was made during reactive hyperemia and in the post-exercise period. In the first mentioned experiments, no agreement between the results by the two methods was obtained. In the experiments in the post-exercise period a highly significant correlation between the two methods was found in each experiment. The mean value of the muscle blood flow, calculated from 133Xenon clearance from six experiments, averages 113 per cent of the flow, measured simultaneously by plethysmography. The standard deviation in the 6 experiments was calculated to ± 63 per cent. The major part of this deviation is ascribed to the difficulty of such a comparison.